Mohamed M Radwan

Medicinal Chemistry, Pharmacy, Microbiology

Ph.D.
36.51

Publications

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    Full-text · Dataset · Jan 2016
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    ABSTRACT: Chemical investigation of the Red Sea soft coral Sarcophyton auritum led to the isolation and structure elucidation of a new ceramide N-((2S,3R,4E,6E)-1,3-dihydroxyhenicosa-4,6-dien-2-yl)tridecanamide (1). Structure elucidation was achieved using spectroscopic techniques, including 1D and 2D NMR and HRMS. The anticonvulsant activity of the isolated ceramide was measured in vivo using the pentylenetetrazole (PTZ)-induced seizure model, where it successfully antagonized the lethality of pentylenetetrazole in mice. In addition, the isolated ceramide showed good anxiolytic activity when used in the light–dark transition box and the elevated plus maze compared to diazepam. The molecular modeling studies for the antiepileptic and antianxiety mechanism of the isolated ceramide suggested a CNS depressing activity possibly through GABA and serotonin receptors modulation. The pharmacological activity of the ceramide involved agonistic activity on GABA-A receptors but not 5HT3 receptors.
    Full-text · Article · Dec 2015 · Bioorganic & medicinal chemistry letters
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    ABSTRACT: An HPLC single-laboratory validation was performed for the detection and quantification of the 11 major cannabinoids in most cannabis varieties, namely, cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), cannabigerol (CBG), cannabidiol (CBD), tetrahydrocannabivarin (THCV), cannabinol (CBN), Δ(9)-trans-tetrahydrocannabinol (Δ(9)-THC), Δ(8)- trans-tetrahydrocannabinol (Δ(8)-THC), cannabicyclol (CBL), cannabichromene (CBC), and Δ(9)-tetrahydrocannabinolic acid-A (THCAA). The analysis was carried out on the biomass and extracts of these varieties. Methanol-chloroform (9:1, v/v) was used for extraction, 4-androstene-3,17-dione was used as the internal standard, and separation was achieved in 22.2 min on a C18 column using a two- step gradient elution. The method was validated for the 11 cannabinoids. The concentration-response relationship of the method indicated a linear relationship between the concentration and peak area with r(2) values of >0.99 for all 11 cannabinoids. Method accuracy was determined through a spike study, and recovery ranged from 89.7 to 105.5% with an RSD of 0.19 to 6.32% for CBDA, CBD, THCV, CBN, Δ(9)-THC, CBL, CBC, and THCAA; recovery was 84.7, 84.2, and 67.7% for the minor constituents, CBGA, CBG, and Δ(8)-THC, respectively, with an RSD of 2.58 to 4.96%. The validated method is simple, sensitive, and reproducible and is therefore suitable for the detection and quantification of these cannabinoids in different types of cannabis plant materials.
    Full-text · Article · Dec 2015 · Journal of AOAC International
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    Full-text · Article · Oct 2015
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    ABSTRACT: The tested alcoholic extract exhibited different potency of cytotoxic activity using the three different cancer cell lines. The highest potency of the tested extract was recorded using the HEPG2 cancer cell line (IC50 = 4.7 μg mL-1). While, HCT-116 and MCF-7 showed weaker cytotoxic effect of the extract with IC50 values of 6.7 and 20 μg mL-1 respectively. Accordingly, the four fractions were tested for their anticancer activity using HEPG2 cancer cell line and the butanol fraction was the most active fraction with IC50 value of 1.5 μg mL-1 compared to doxorubicin (0.4 μg mL-1)(Figure 1). Three known compounds (1-3) were isolated and chemically identified as 2-hydroxyphenyl D-glucopyranoside (1), Quercetin 3,7-O-α-L-dirhamnoside (2), soyasaponin I (3) from the butanol extract. Also the ethylacetate fraction had a strong activity (IC50 =2.9 μg mL-1) from which one new compound (4) was isolated and chemically identified as 4,4`-dihydroxy-7-methoxy-isoflavanone-4`-glucupyranoside. While, the petroleum ether and chloroform extracts displayed weaker activity with IC50 values of 4.8 and 10.5 μg mL-1 respectively
    Full-text · Conference Paper · Oct 2015
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    ABSTRACT: Nine oxygenated cannabinoids were isolated from a high potency Cannabis sativa L. variety. Structure elucidation was achieved using spectroscopic techniques, including 1D and 2D NMR, HRMS and GC-MS. These minor compounds include four hexahydrocannabinols, four tetrahydrocannabinols, and one hydroxylated cannabinol, namely 9α-hydroxyhexahydrocannabinol, 7-oxo-9α-hydroxyhexa-hydrocannabinol, 10α-hydroxyhexahydrocannabinol, 10aR-hydroxyhexahydrocannabinol, Δ(9)-THC aldehyde A, 8-oxo-Δ(9)-THC, 10aα-hydroxy-10-oxo-Δ(8)-THC, 9α-hydroxy-10-oxo-Δ(6a,10a)-THC, and 1'S-hydroxycannabinol, respectively. The latter compound showed moderate anti-MRSa (IC50 10.0μg/mL), moderate antileishmanial (IC50 14.0μg/mL) and mild antimalarial activity against Plasmodium falciparum (D6 clone) and P. falciparum (W2 clone) with IC50 values of 3.4 and 2.3μg/mL, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Full-text · Article · Sep 2015 · Phytochemistry
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    ABSTRACT: Bioassay-guided fractionation of the marine sponge Lendenfeldia dendyi and the soft coral Sinularia dura resulted in the isolation of five polybrominated diphenyl ethers (1–5). The structures of the isolated compounds were determined using spectroscopic methods (1D and 2D NMR) and HRMS analyses. The absolute structures of compounds 1 and 2 were confirmed by X-ray analysis. Antimicrobial testing of the isolated compounds along with the acetylated derivative of compound 2 (2a) indicated that they displayed a significant and selective activity against methicillin-resistant Staphylococcus aureus (MRSa) with IC50 values of <0.04–1.18 µM. The antimalarial and antileishmanial activities of the isolated compounds were also evaluated.
    Full-text · Article · Sep 2015 · Medicinal Chemistry Research
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    ABSTRACT: Extracts of Egyptian marine organisms from the Red Sea were screened for their anticancer activity using sulforhodamine B assay. The extract of the Red Sea sponge Spheciospongia vagabunda possessed promising anticancer activity against HepG2 (liver cancer cell line) and MCF-7 (breast cancer cell line). Isolation of three new ceramides: N-[(2S,3S,4R)-1,3,4-trihydroxytetradecan-2-yl] tridecanamide (1), (R)-2′-hydroxy-N-[(2S,3S,4R)-1,3,4-trihydroxypentacosan-2-yl] octadecanamide (2) and (R,Z)-2′-hydroxy-N-[(2S,3S,4R)-1,3,4-trihydroxytricosan-2-yl) nonadec-10-enamide (3) was accomplished via bioassay-guided fractionation. Structure elucidation was achieved using spectroscopic techniques, including 1D and 2D NMR and HRMS. Compounds 2 and 3 displayed high potential cytotoxicity against HepG2 (IC50 24.7 and 21.3 µM, respectively) and MCF-7 (IC50 26.8 and 29.8 µM, respectively), compared with doxorubicin as control drug.
    Full-text · Article · Sep 2015 · Medicinal Chemistry Research
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    ABSTRACT: The n-hexane extracted volatile fraction of high potency Cannabis sativa L (Cannabaceae). was assessed in vitro for antifungal, antibacterial and antileishmanial activities. The oil exhibited selective albeit modest, antifungal activity against Cryptococcus neoformans with an IC50 value of 33.1 μg/mL. Biologically-guided fractionation of the volatile fraction resulted in the isolation of three major compounds (1-3) using various chromatographic techniques. The chemical structures of the isolated compounds were identified as α-humulene (1), β-caryophyllene (2) and caryophyllene oxide (3) using GC/FID, GC/MS, 1D- and 2D-NMR analyses, respectively. Compound 1 showed potent and selective antifungal activity against Cryptococcus neoformans with IC50 and MIC values of 1.18 μg/mL and 5.0 μg/mL respectively. Whereas compound 2 showed weak activity (IC50 19.4 μg/mL), while compound 3 was inactive against C. neoformans.
    Full-text · Article · Aug 2015 · Records of Natural Products
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    ABSTRACT: Solanum cernuum Vell. (Solanaceae) is a Brazilian medicinal plant, traditionally known as'"panaceia". Its folk name is probably due to its wide range of applications in traditional medicine including the treatment of ulcers. To evaluate the gastroprotective activities of the hydroethanolic extract (ESC) of S. cernuum and its major isolated compounds using in vivo gastric ulcer models. The ESC extract was obtained by maceration followed by percolation of the dried and powdered leaves of S. cernuum in ethanol/water (7:3). The major compounds in the extract were isolated by applying various preparative chromatographic techniques. The gastroprotective activity was evaluated in mice using different gastric ulcer-induced models. The anti-Helicobacter pylori activity was performed using the agar-well diffusion and broth microdilution methods. The ESC extract showed gastroprotective effects in the assay of acute gastric ulcer-induced by HCl/EtOH, nonsteroidal anti-inflammatory drug, and acetic acid-induced chronic ulcer protocols. The results also demonstrated that the gastroprotection induced by ESC extract is related to the activity of nitric oxide and endogenous sulfhydryls, which are important gastroprotective factors. The ESC extract and the alkaloid cernumidine did not show activity against Helicobacter pylori in the concentrations tested. The present study showed that the crude extract of S. cernuum possessed gastroprotective activity which corroborating the traditional use of this plant for the treatment of gastric ulcers. The isolated flavonoids, quercitrin and afzelin as well as the phenylpropanoid, isoferulic acid are suggested to be the compounds responsible for the gastroprotective activity of S. cernuum extract. Copyright © 2015. Published by Elsevier Ireland Ltd.
    Full-text · Article · Jul 2015 · Journal of ethnopharmacology
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    Full-text · Dataset · Jun 2015
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    ABSTRACT: Seven new naturally occurring hydroxylated cannabinoids (1-7), along with the known cannabiripsol (8), have been isolated from the aerial parts of high-potency Cannabis sativa. The structures of the new compounds were determined by 1D and 2D NMR spectroscopic analysis, GC-MS, and HRESIMS as 8α-hydroxy-Δ(9)-tetrahydrocannabinol (1), 8β-hydroxy-Δ(9)-tetrahydrocannabinol (2), 10α-hydroxy-Δ(8)-tetrahydrocannabinol (3), 10β-hydroxy-Δ(8)-tetrahydrocannabinol (4), 10α-hydroxy-Δ(9,11)-hexahydrocannabinol (5), 9β,10β-epoxyhexahydrocannabinol (6), and 11-acetoxy-Δ(9)-tetrahydrocannabinolic acid A (7). The binding affinity of isolated compounds 1-8, Δ(9)-tetrahydrocannabinol, and Δ(8)-tetrahydrocannabinol toward CB1 and CB2 receptors as well as their behavioral effects in a mouse tetrad assay were studied. The results indicated that compound 3, with the highest affinity to the CB1 receptors, exerted the most potent cannabimimetic-like actions in the tetrad assay, while compound 4 showed partial cannabimimetic actions. Compound 2, on the other hand, displayed a dose-dependent hypolocomotive effect only.
    Full-text · Article · May 2015 · Journal of Natural Products
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    ABSTRACT: The aim of the present study was to determine if Cuscuta pedicellata extract has an effect on body weight and serum lipid profile in the HFD-fed rats’ animal model. The ethanol extract of C. pedicellata exhibited a significant reduction in body weight and serum lipid profile in this model. The n-hexane/EtOAc (1:1), EtOAc and MeOH/EtOAc (1:1) fractions were also active, while the MeOH fraction showed no beneficial effect. Bioactivity-guided fractionation leads to the isolation of ten pure compounds: naringenin (1), kaempferol (2), aromadenderin (3), quercitin (4), 3,5,7,3′,5′-pentahydroxy flavanone (5), naringenin -7-O-β-d-glucoside (6), aromadenderin -7-O-β-d-glucoside (7), Taxifolin -7-O-β-d-glucoside (8), kaempferol -3-O-β-d-glucoside (astragalin), (9) and quercitin -3-O-β-d-glucoside (isoquercitrin) (10). This is the first report of compounds 1, 3, 5, 6, 7, and 8 in Cuscuta pedicellata. Compound 1 > compound 8 > compound 3 > compound 7 > compound 4 > compound 2 are responsible for the potency of the ethanol extract, while compound 6 was only effective in reducing the total cholesterol serum levels but not effective in reducing the level of triglycerides or the body weight. Our data confirmed the anti-obesity effect of C. pedicellata reported by the Egyptian population and identified the compounds responsible for this activity.
    Full-text · Article · May 2015 · Medicinal Chemistry Research
  • YH Wang · B Avula · MA ElSohly · MM Radwan · M Wang · AS Wanas · Z Mehemdic · IA Khan

    No preview · Article · Apr 2015 · Planta Medica
  • B Awad · AK Ibrahim · E Sand · AS Wanas · MM Radwan · M Elsohaly · SA Ahmed

    No preview · Article · Apr 2015 · Planta Medica
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    ABSTRACT: Purpose: The aim of this work was to develop an HPLC method for the analysis of 11 cannabinoids and its application of the method for profiling different cannabis extracts. Methods: Eleven cannabinoids (cannabidiolic acid, CBDA ; cannabigerolic acid, CBGA ; cannabigerol, CBG ; cannabidiol, CBD ; tetrahydrocannabivarian, THCV ; cannabinol, CBN ; delta-9-trans-tetrahydrocannabinol, Δ9-THC ; delta-8-transtetrahydrocannabinol, Δ8-THC ; cannabicyclol, CBL ; cannabichromene, CBC ; and tetrahydrocannabinol acid A, THCAA ) were prepared at 9 different levels with internal standard. The peaks for the cannabinoids were observed at 220 nm. Results: All the 11 cannabinoids were successfully analyzed by HPLC-UV method and the method was validated. Thirteen different cannabis extracts were analyzed by this method and all the above cannabinoids except CBL (which was detected only in one extract) were successfully quantitated in these extracts. Conclusion: The method is reproducible and can be used successfully to analyze cannabis extracts. Acknowledgements The authors are thankful to Candice Tolbert and Shahbaz Gul for their technical assistance and data collection and assembly. Abstract Link: http://abstracts.aaps.org/Verify/AAPS2014/PosterSubmissions/W4215.pdf
    No preview · Conference Paper · Nov 2014
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    ABSTRACT: Cannabis has been around for thousands of years and has been used recreationally, medicinally, and for fiber. Over 500 compounds have been isolated from Cannabis sativa with approximately 105 being cannabinoids. Of those 105 compounds, Δ9-tetrahydrocannabinol has been determined as the primary constituent, which is also responsible for the psychoactivity associated with Cannabis. Cannabinoid receptors belong to the large superfamily of G protein-coupled receptors. Targeting the cannabinoid receptors has the potential to treat a variety of conditions such as pain, neurodegeneration, appetite, immune function, anxiety, cancer, and others. Developing in vitro bioassays to determine binding and functional activity of compounds has the ability to lead researchers to develop a safe and effective drug that may target the cannabinoid receptors. Using radioligand binding and functional bioassays, a structure–activity relationship for major and minor cannabinoids was developed.
    Full-text · Article · Sep 2014 · Medicinal Chemistry Research
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    ABSTRACT: Bioassay guided fractionation of the ethanolic extract of Asphodelus microcarpus Salzm. et Viv. (Xanthorrhoeaceae or Asphodelaceae) resulted in isolation of five compounds identified as asphodosides A-E (1-5). Compounds 2-4 showed activity against methicillin resistant Staphylococcus aureus (MRSA) with IC50 values of 1.62, 7.0 and 9.0 mu g/mL, respectively. They also exhibited activity against Staphylococcus aureus (non-MRSA) with IC50 values of 1.0, 3.4 and 2.2 mu g/mL, respectively. The structure elucidation of isolated metabolites was carried out using spectroscopic data (1D and 2D NMR), optical rotation and both experimental and calculated electronic circular dichroism (ECD).
    Full-text · Article · Sep 2014 · Phytochemistry
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    ABSTRACT: Three natural cembranoids from the Red Sea soft coral Sarcophyton glaucum namely (1S,2E,4R,6E,8R,11S,12R)-8,12-epoxy-2,6-cembradiene-4,11-diol, (1S,2E,4R,6E,8S,11R,12S)-8,11-epoxy-4,12-epoxy-2,6-cembradiene and (1S,4R,13S)-cembra-2E,7E,11E-trien-4,13-diol were evaluated for their inhibitory effects on mouse melanoma B16F10 cell growth. Results show that all the cembranoids strongly inhibit viability of melanoma cells particularly during 48 -72 hrs treatment and also inhibit de novo DNA synthesis and PARP activity and stimulate fragmentation of DNA. (1S,2E,4R,6E,8R,11S,12R)-8,12-epoxy-2,6-cembradiene-4,11-diol was not cytotoxic to monkey kidney CV-1 cells at the concentration that produces the anti-melanoma effects which indicates that this compound may be a good candidate for further development. (1S,2E,4R,6E,8S,11R,12S)-8,11-epoxy-4,12-epoxy-2,6-cembradiene and (1S,4R,13S)-cembra-2E,7E,11E-trien-4,13-diol were found to be cytotoxic to healthy cells.
    Full-text · Article · Aug 2014 · Natural product communications

  • No preview · Article · Aug 2014 · Planta Medica

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